The invention relates to an emulsion and a method for forming an emulsion of a viscous crude hydrocarbon in an aqueous buffer solution.
Large reserves of crude hydrocarbons exist which, in their natural state, are very viscous. These hydrocarbons are capable of being processed into useful end products. However, the viscous nature of such viscous crude hydrocarbons makes it difficult to transport the hydrocarbons in conventional pipelines to stations where the viscous crude hydrocarbons can be treated. Typical viscous crude hydrocarbons may be characterized by the following chemical and physical properties: C wt. % of 78.2 to 85.5; H wt. % of 9.0 to 10.8; O wt. % of 0.26 to 1.1; N wt. % of 0.50 to 0.70; S wt. % of 2.00 to 4.50; Ash wt. % of 0.05 to 0.33; Vanadium, ppm of 50 to 1,000; Nickel, ppm of 20 to 500; Iron, ppm of 5 to 100; Sodium, ppm of 10 to 500; Gravity, API of 1.0 to 16.0; Viscosity (cST), 122.degree. F. of 100 to 5,000,000; Viscosity (cST), 210.degree. F. of 10 to 16,000; LHV (BTU/LB) of 15,000 to 19,000; and Asphaltenes, wt. % of 5.0 to 25.0.
From a consideration of the above, particularly the viscosity, the difficulties in transporting a material in conventional pipelines can be appreciated.
One solution to the problem of transporting viscous crude hydrocarbons has been to form emulsions of the hydrocarbon in water. Such emulsions exhibit greatly reduced viscosity which, of course, facilitates the transport of same. Unfortunately, such emulsions require emulsifiers to be stable, and commercial emulsifiers conventionally used in forming such an emulsion are expensive. The added cost of the commercial surfactant naturally makes the option of forming emulsions to transport viscous crude hydrocarbons less attractive.
It is desirable to provide an emulsion of the viscous crude hydrocarbon in water which does not require commercial surfactants/emulsifiers for stability. Such an emulsion would provide an economical method for transporting the viscous crude hydrocarbon and, therefore, a more economical method for processing the viscous crude hydrocarbon into useful end products.
Accordingly, it is the principal object of the present invention to provide a transportable stable emulsion of a viscous crude hydrocarbon in water which does not require commercial emulsifiers for stability.
It is a further object of the invention to provide such an emulsion which is easily broken once it is transported to the desired destination.
It is a still further object of the invention to provide such an emulsion having two distinct droplet size populations, and, therefore, improved viscosity characteristics.
It is another object of the invention to provide a method for forming such an emulsion.
Other objects and advantages will appear hereinbelow.